Flexible conduit and method of making the same



Aug. 18, 1931. E. JAMES 1,819,175

FLEXIBLE coNDUIT AND METHOD oF MAKING THE SAME 4' 3 -Filed Nov. 20, 192eiNvENToR f BY :Ph/v? TTORNEYS Patented Aug. 18, 193i UNITED STATESPATENT oFFlc EDWARD JAMES'OF CLEVELAND, OHO, .ASSIGNOR, BY MESNEASSIGNMENTS, T0 HAROLD ELNO SMITH, F CLEVELAND HEIGHTS, OHIO CONDUIT-AND METHOD OF MAKING- SAME Application filed November 20, 1926. SerialNo. 149,572.

This invention relates to exible conduit and to a method of makin-g thesame. It is particularly concerned with flexible, fluidconfinin conduitformed in part from more or less r1gid tubing. i

Heretofore iexible conduit has been made from material of relativelylittle stiffness,

such as cloth, so that it could bend laterally,`

forces only by absorbing some of the forces itself. Moreover, the4coiled wire did not uniformly distribute stresses in the conduit, butoften localized the stresses with the reslt that the life of the conduitwas quite s ort.

I have discovered, however, that extremely A flexible, huid-confiningconduit can be made from stiff tubing of thick, hardpiiber, metal orvulcanized brous material.. The'inherent rigidity of such'tubingeffectively resists deforming stresses and prevents the tubing frombeing creased, kinked or flattened. The

conduit is surprisingly flexible and possesses unusually long life bothdue, I believe, large- -ly to the cooperating relationship existingbetween the tube and coiled member or members in devices of myinvention.

My invention may be well understood from a description of 'a deviceembodying it and a method of making such a device. Briefly, such adevice comprises a tube of iuid-conning material s'pirally corrugatedand having one or more coiled members assembled with the corrugations ofthe tube in such manner and condition that a relatively powerful forceas compared with the expansive tendency of the tube is exerted, therebycausing axial contraction of 5 the conduit. A single coiled member mayeach other.

be used when the tubing is sufficiently rigid .or stiff to retain it inplace with the corrugations, but when one or more coiled members areemployed on each side of the tubing, more flexible tubing material, evencloth, -can be used. The coils may be composed of spring wire, fiber andsimilar material having close coiled convolutions initially,'andpossessing suiicient resiliency to tend to return with force to itsinitial w position and form when distorted, as for example when the coilis expanded axially and the convolutions separated.

The method comprises briefly'the provision of a tube of fluid-confiningmaterial in which, if made by winding sheet material about a form, thematerial preferably is Pwound with its ends substantially parallel withthe axis of the tube or straight as contrasted with curving spirallyabout the tube. v v

One or more short coiled members are provided, the convolutions of eachmember being normally in substantial contact with The outside diameterof the member which is to go inside the tube should be only slightlyless'than the inside diameter of the tube while the inside diameter ofthe member to go outside of the tubes should be somewhat less than theoutside diameter of the tube. IV prefer to select coiled mem seA bers ofsuiiicient stiffness, resiliency or axially contractile strength tocontrol the action of the tubing and to contract the same axially. Ofcourse, the size of or material constituting such members should bevaried in accordance with the size and nature of material constitutingthe tubing so" as to af'- ford the desired action. A length of suitabletubing somewhat longer than the final desired length is then assembledwith one or more shorter coiled members which, for example, need notexceed about one-eighth of the length of the tubing.' When the conduitis to have an inside coiled member, the latter may be placed in; one endof the tubing and secured .thereto-and then the tube may be corrugatedspirally. When this `corrugating begins near or at the end thereof andover the'inner coil and progresses toward the ,other end, the tubing isprogres- "combination with! flexible metal tubing,l

sively forced down between lthe convolutions of the coiled member andthe coiled memberis thereby expanded axially to apis placed about thetube progressively from one end of the tube to the other immediatelyfollowing the formation of the corrugations therein, the convolutionsbeing separated only as fast `as they are placed on the tube. Obviouslytwo or ymore coiled members can thus be assembled with a tube in onecomplete operation. It is also obvious, that one coiled member may bemuch stiffer than the other if desired since the contractile actions,

are additive andv opposite to the normal tendency of the tube to expandaxially after being corrugated. Such contractile forces act to controlthe movement of the' tube and tend to preserve a bellows like formationAof the tube which is conducive to great flexibility even with normallyinflexible tube materials.A

My Iinvention may also be carried out in where the metal tubing isplaced within a fiber tube, which is corrugated and has a contractilecoiled member placed outside the tube in the corrugations. The tubeserves to confine fluids without requiring the expensive packing in themetal tube common at present and prevents the normal twistin tendency ofthe metal tubing and the coile member insures permanent assembly of theparts and increases. the flexibility of the complete device.

@ther-advantages of my invention will become apparent as thefollowingdescription of several embodiments thereof pro-N gresses, referencebeing made to the accompanying drawings in which like referencecharacters are employed to designate like parts throughout the same.

Fig. 1 is an elevationpartly in section of a portion of a conduitforming one embodiment of my invention.

Fig. 2 is an end view of the same.

Fig. 3 is an enlarged fragmentary section,

of a form of conduit comprising another embodiment of my invention.v

Fig. 4 is an enlarged fragmentary view of a third embodiment of myinvention.

Fig..5*is an enlarged fragmentary view of a fourth embodiment of myinvention.

Fig. 6 is an enlarged fragmentary view of a fifth embodiment of myinvention.

Fig. 7 is an enlarged fragmentary section amarre of tubingcomprisingtlfe sixth embodiment of my invention.

Fig. 8 is an enlarged fragmentary section of tubing.

Fig. 9 is an enlarged fragmentary section of another embodiment of myinvention.

Referring now more particularly to Figs. 1 and 2, which illustrate oneembodiment of my invention, I provide an inner normally closed coil 2 ofspring wire and a similar outer normally closed coil spring 3.Interposed between these coils is a tube 1 of ber material corrugated asat 4;,fsubstantially throughout its length. The tube is formed of sheetmaterial with the ends extending parallel to the longitudinal axis ofthe tube, as shown at 5. 'Ihe outer coil 3 is/initially of lesserdiameter thanthe outside diameter of the tube l, so that it exerts aradially contracting force on the tube when corrugated.' 'Ihe inner coil2 is almost as large in diameter initially as the interior of the tubebefore itis corrugated.

In Fig. 3 I have illustrated a second embodiment of my invention, whichcomprises acorrugated tube 10 of suitable material, having an outernormally closed coil 11, and inner normally closed coils 12 and 13. Theouter coil is vformed of a strip of flexible ber material havingconsiderable rigidityl and contractile strength. This strip ispreferably bowed or rolled into concavo-convex cross section, so thatwhen applied to the corrugations of the tube, its concave surface willconform to the contour of the corrugations, the edgesl of the stripextending well down into' the depressions between' the corrugations. Itwill be noted in connection Awith this embodiment that I provide twocoil springs in extended position within the tube `10, the convolutionsof these coils being seated alternately in depressions in tube 10.

In Fig. 4 which illustrates another embodiment of my l invention, Iprovide an! outer normally closed coil spring 15, and an inner normallyclosed coil member 16 composed of a strip of material such as libre, thestri being formed as shown in the figure to con orm to the walls of thedepressions on the interior of the tube. The longitudinal edges oftheconvolutions forming the inner coil extend well up onto the apices ofthe corrugations in the tube 10, thus protecting the'latter from wear.

In Fig. 5 I have illustrated another embodiment of my invention, inwhich I have shown inner and outer normally closed coils formed of astrip of suitable material, such as metal or fibre, the cross sectionsof either strip bein concavo-convex, the concave surfaces of t e stripsbeing shaped to conform to the contour of the apices or, peaks of therespective corrugations of the tube 10, on which they are to seat andwith slightly rounded edges to prevent wear on the tube.

corrugated`tube is provided with inner4 and outer coils and 21,respectively, the inner coil comprising a normally closed A metal springand the outer coil comprising a acfstrip of flexible fibrous material ofconcavo convex cross section.

In Fig. 8 I have illustrated still another embodiment of my inventionwhich consists in providing a corrugated tube 10 as hereinbeforedescribed with coils and 31 substantially triangular in cross sectionwith the bases of the said coils forming a substantially smoothcylindrical surface on the respective inner and outer walls of theconduit, when the coils are in assembled positions. The apex of eachcross section of .either the inner or outer coils is preferably roundedas at 33 to support the tubing without cutting the same. l

In Fig. 9 I have illustrated another ernbodiment of my invention whichconsists in applying a normally closed spring 43 to the i convolutionsof a fiber tube 44 surrounding a exible metal tube of the interlockingtype that is a tube composed of a spirally wound metal strip whoseadjacent convolutions interlock. In this embodiment of my inveny tion,the conduit maybe constructed of any .suitable form of interlockingconvolutions,

one type of which is shown in Fig. 9, as consisting of anarched'jportion 41 of each convolution overlapp g and interlocking withan upwardly extending portion 42 o the next succeeding convolution. Anormally closed coil spring 43 is extended and its convolutions disposedbetween the arched portions of respective adjacent interlocking sections40. The corrugated tube 44 flexibly seals the joints between therelativel movable interlocln'ng sections, and thus o viates any packingin the metal tubing for conining fluid.

Various other changes may be. made in the details of construction-of myinvention without departing from the spirit thereof or the scope of theappended claims.,

What is claimed is: i

1. A iiexible conduit comprisinga spi-l corrugations of the tube, thesaid coil having a greater tendency to contract than the tendency of thetube to expand axially.

3. A iiexible conduit comprising a tube corrugated spirally and a coiledmember disposed therewithin,` the convolutions of the coil beingseparated by the corrugations of the tube and the coil being maintainedin a condition of axial tension.

4. A liexible conduit comprising a Huidtight tube corrugated spirally,and a coiled member operatively associated with the corrugations of thetube, the said coiled member having its convolutions spaced apart andbeing axially tensioned.

5. A iiexible conduit comprising a tube spirally corrugated and aplurality of coiled members disposed within and without the said tube.and operatively associated with the said corrugations, the said coiledmembers having their convolutions spaced apart and being tensionedaxially by the corrugations of the tube.

6. A tube of spirally corrugated material,

said tube being normally rigid if uncorru-l gated, and a helical coil ofspring wire having its convolutions located in such corrugations andtensioned against the walls thereof both radially and longitudinallywhereby said tube is rendered flexible.

7. A conduit comprising a spirally corrugated tube, said tube beingrelatively rigid if uncorrugated, and a pluralityof yielding membersdisposed within said tube and operatively associated and held apart andaxially and radially tensioned by said corrugations.

In testimony whereof I hereunto aix my signature this 18th day ofNovember, 1926.

EDWARD JAMES.

